Background: This study examined the socio-demographic characteristics and attitudes of primary care giving fathers and non-primary care giving fathers and the quality of their interaction with their infants.

Method: Two groups of fathers of 11.9-month old infants were compared - 25 primary care giving fathers (20 h per week or more of sole infant care) and 75 non-primary care giving fathers - with regard to socio-demographic characteristics, attitudinal differences and father-infant interaction during play and mealtimes. The quality of father-child interaction in relation to the total number of hours of primary care provided by fathers was also examined.

Results: Primary care giving fathers had lower occupational status and earned a smaller proportion of the family income but did not differ in educational level or attitudes compared with non-primary care giving fathers. There were no differences between the partners of the two groups of fathers on any variables, and their infants did not differ in temperament. Primary care giving fathers and their infants exhibited more positive emotional tone during play than non-primary care giving fathers, although fathers did not differ in responsivity. There were no differences between the groups during mealtimes. There was a positive association between total number of child care hours provided by all fathers and infant positive emotional tone.

Conclusions: Primary and non-primary care giving fathers were similar in many respects, but primary care giving fathers and their infants were happier during play. This suggests a possible link between the involvement of fathers in the care of their children and their children's emotional state. The finding of a trend towards increased paternal happiness with increased hours of child care suggests that there may also be a gain for fathers who are more involved in the care of their infants. Further research is needed to determine whether these differences ultimately have an effect on children's development.